Verizon slammed Huawei's lawsuit against it as a "PR stunt" on Thursday, claiming it is a "sneak attack on our company and our nation."
Huawei sued Verizon in the U.S. alleging the American telecoms firm infringed patents held by the Chinese network equipment maker. The lawsuit was filed in the early hours of Thursday morning.
But in a strongly-worded statement, Verizon took aim at Huawei's actions.
"Huawei's lawsuit filed overnight, in the very early morning, is nothing more than a PR stunt," a Verizon spokesperson told CNBC by email.
"This lawsuit is a sneak attack on our company and our nation. The action lacks merit, and we look forward to vigorously defending our company and our nation."
In a follow up statement, Verizon called Huawei's lawsuit an attack on the "entire tech ecosystem."
"Huawei's real target is not Verizon; it is any country or company that defies it," the spokesperson said.
Huawei claims it has been trying to negotiate royalty payments with Verizon "for a significant period of time" but the two sides were unable to reach an agreement.
The Chinese firm holds over 11,000 patents in the U.S., many of which are crucial for the running of mobile networks. While Verizon doesn't buy directly from Huawei, it may purchase products from vendors using the Chinese firm's patented technology.
Huawei says the alleged infringements relate to 12 patents in areas from computer networking to video communications, claiming that Verizon has "greatly profited" from the use of these.
The U.S. government has accused Huawei of being a national security threat claiming its equipment could be used by China for espionage on Americans. Huawei has repeatedly denied the claims. Still, Washington put the firm on a blacklist that restricts its access to American technology.
Huawei has been using legal means to fight back, including suing the U.S. government last year over a law that prohibits federal agencies from buying the company's gear.
Bringing legal action to American firms could be a way for Huawei to go on the front foot against the U.S. Last year, a source at Huawei told CNBC that there "has been consideration about the role of IP and what it mean(s) in terms of the U.S. and Huawei."